As cobras são " ordenhadas " exprimindo os dentes contra uma superfície emborrachada (ou plana) e, em seguida, massageando as glândulas de veneno, a fim de coletar o veneno da cobra. No mundo real, isso seria usado para produzir anti-veneno. No mundo mágico, Voldemort usa o veneno de Nagini para criar sua poção corporal rudimentar
Mais tarde, aprendemos o uso do veneno;
Wormtail was able to follow the instructions I gave him, which would return me to a rudimentary, weak body of my own, a body I would be able to inhabit while awaiting the essential ingredients for true rebirth … a spell or two of my own invention … a little help from my dear Nagini’ – Voldemort’s red eyes fell upon the continually circling snake – ‘a potion concocted from unicorn blood, and the snake venom Nagini provided … I was soon returned to an almost human form, and strong enough to travel. Harry Potter and the Goblet of Fire